Hey T^2, I was just thinking about your Pavlovian experience.
I know exactly what you are saying. I actually thought about it more and see that even with the ringing of a phone. How people trigger to pick up the phone, even if it might be inconvenient or even inappropriate to do so at the time (for what ever reason).
Take that a step further and people die because they react to these things in such an automatic way (ie. driving down the road and the phone dings because of a text, the look down to react and...)
Just wanted to validate your feelings about the IM thing. Myself, I continue to maintain that any comm with my X is via email.